When you get ready to back under the semi trailer you should line up?

4. When you get ready to back under the semi trailer you should line up: A About 12 degrees off the line of the trailer.

When backing under the trailer you should?

Before backing the tractor under the trailer, adjust the landing gear to position the trailer at the proper height. The trailer should be just low enough that it will be raised slightly by the tractor when the tractor backs under it.

How should you test the tractor semi trailer connector for security?

How should you test the tractor semi trailer connection for security? Pull gently forward in low gear against the locked trailer brakes, then look at it carefully.

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Which part of the kingpin should the locking jaws?

Check to make sure of the following: There is no space between the upper and lower fifth wheel, the fifth wheel jaws have closed around the shank of the kingpin, the locking lever is in the “lock” position, and the safety latch is in position over the locking lever.

What would happen if the emergency air line between the tractor and trailer came apart?

What will happen if the air lines are crossed when you hook up to an old trailer? a. The hand valve will apply the tractor brakes instead of the trailer brakes. … If the trailer has no spring brakes, you could drive away but you would not have trailer brakes.

What might happen if the trailer is too high when you try to couple?

In addition to incorrect coupling, if a trailer is too high off the ground and you try to back into it, you may cause damage as the rear of your truck cab could strike the front of the trailer. Further, the trailer king pin may become stuck in front of the fifth wheel plate which can be a costly and time wasting error.

What is off tracking or cheating?

When any vehicle turns, its rear wheels will follow a shorter path than its front wheels. This is called off-tracking or “cheating.” The longer the vehicle, the greater the difference. In a combination vehicle, the trailer’s wheels will off-track more than the tractor’s rear wheels.

How much space should be between the upper and the lower fifth wheel plates?

There should be no space between the upper and lower fifth wheel.

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When you turn suddenly while pulling doubles which trailer is most likely to turn over?

When you turn suddenly while pulling doubles, which trailer is most likely to turn over? The rear trailer is twice as likely to turn over as the tractor.

What happens if the service airline comes apart?

If the service air line comes apart while you are driving a combination vehicle but the emergency line stays together, what will happen right away? A Nothing is likely to happen until you try to apply the brakes. B You’ll come to a complete stop.

What gear should the tractor transmission be in after you have uncoupled?

15. You want to inspect the trailer support. You should place the tractor transmission in which gear after you have uncoupled the trailer? Neutral.

When connecting the glad hands press the two seals?

When connecting the glad hands, press the two seals together with the couplers at a 90 degree angle to each other. A turn of the glad hand attached to the hose will join and lock the couplers. If you do cross the air lines, supply air will be sent to the service line instead of going to charge the trailer air tanks.

Why should you lock the tractor glad hands to each other or dummy couplers when you are not towing a trailer?

Why should you lock the tractor glad hands (or dummy couplers) to each other when you are not towing a trailer? A The connected brake circuit becomes a back up air tank. B If you did not, you could never build system pressure.

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What happens when you cross the air lines of an older trailer without spring brakes?

You cross the air lines when hooking up to an old trailer. What will happen? If the trailer has no spring brakes, you could drive away buy you wouldn’t have trailer brakes. … In normal driving, some drivers use the trolley (hand) valve before the brake pedal in order to prevent trailer skids.

What is the emergency air line?

Emergency air line:

The emergency line (also called the supply line) has two purposes: (1) To supply air to the trailer air tanks, and (2) to control the emergency brakes on combination vehicles. Loss of air pressure in the emergency line causes the trailer emergency brakes to come on.

Special equipment and operation